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Farhan on SolderSmoke videos

 

Farhan Describes the BITX23 -- His New 2 Meter SSB Transceive


Talking to Farhan -- May 16, 2023: High School DC RX, uBITX, Franklin Oscillator, Glue Sticks, More

--
73
??? Bob? KD8CGH
 

Yet another on sBITX

--
73
??? Bob? KD8CGH
 

In the video of the interview, a document is shown on the PC screen named “The BITX23 – Going VHF”.

I could not find that document on line, is it available?

Thanks,
Chris PA3CRX
 

It might be a false flag.

Clark Martin
KK6ISP

On Jul 3, 2023, at 12:49 AM, Chris van den Berg <aar-dig@...> wrote:

In the video of the interview, a document is shown on the PC screen named “The BITX23 – Going VHF”.
I could not find that document on line, is it available?
 

The circuit and the details are on?
I cant post the original article online as it is copyright of qrparci.
I will write a fresh article for my own website.
- f

On Mon, Jul 3, 2023, 9:50 PM Clark Martin <kk6isp@...> wrote:
It might be a false flag.

Clark Martin
KK6ISP

> On Jul 3, 2023, at 12:49 AM, Chris van den Berg <aar-dig@...> wrote:
>
> In the video of the interview, a document is shown on the PC screen named “The BITX23 – Going VHF”.
> I could not find that document on line, is it available?
>







 

Reference schematic and code on Github:

ron
KA3JIJ
 

Thanks Ashar, looking forward to it!

At least it was not my poor way of searching J

?

Your articles contain the decisions you made and some background information about the individual circuits. Interesting to read.

(And I am also curious about the easy loading system to program the Arduino).

Chris PA3CRX
 

For some unknown reason, the schematic could no longer be downloaded by me...

I remember that the BFO signal was not generated by the SI5351 but by an crystal oscillator. What is (or could be) the reason for that?

Thanks,
Chris PA3CRX
 

I just downloaded the files.

FYI the schematic has more than a few errors, lines ji=ned that should not be
and other drawing errors.

Why crystal BFO, simple the SI570 is a single DPLL, the 5351 is less than ideal at 2m
but it can produce multiple outputs as typically used at HF.

--
Allison
------------------
Please use the forum, offline and private will go to bit bucket.
 

Thanks Allison,
I had not noticed Si570 was used, so that makes sence :-)

Interresting to hear that SI5351 is less ideal at 2 mtr. Do you have more information about that?

Thanks
Chris
 

Basic answer is that the 5351 has higher phase noise (jitter).
ITs adequate for HF use but at higher frequencies where the ambient
and galactic noise are lower it handicaps the receiver performance.
This is old news.

The Si570 is roughly 10x lower jitter ans as a result less phase noise.

Compared to a good crystal or VFO they are an order of magnitude nosier.
The price paid for stability and digital tuning.

--
Allison
------------------
Please use the forum, offline and private will go to bit bucket.
 

Allison,
One thing that has always troubled me was, why would a crystal oscillator me noisier than a free running LC oscillator? My claim is based on my own observations, perhaps I got unlucky here.
It appears counter intuitive. Crystal oscillators are more stable and hence they should have been less noisier.


On Wed, Nov 8, 2023, 9:22 PM ajparent1/kb1gmx <kb1gmx@...> wrote:
Basic answer is that the 5351 has higher phase noise (jitter).
ITs adequate for HF use but at higher frequencies where the ambient
and galactic noise are lower it handicaps the receiver performance.
This is old news.

The Si570 is roughly 10x lower jitter ans as a result less phase noise.

Compared to a good crystal or VFO they are an order of magnitude nosier.
The price paid for stability and digital tuning.

--
Allison
------------------
Please use the forum, offline and private will go to bit bucket.

 

On Wed, Nov 8, 2023 at 07:52 AM, ajparent1/kb1gmx wrote:
This is old news.
Sorry I was not aware of that Allison.
Digging further on the internet about phase noise with SI5351 I found different information.
In I even red it is a myth!
Perhaps one of the biggest (probable) myths, is that the Si5351A has
high phase noise so we shouldn't use it if we care about noise! Of
course every application does have different requirements and trade-offs
are always present. Base the trade-offs on reality though not on rumour.

Most of the experiments were done in the HF bands but I get the picture.
However, if we make a simple transceiver, what will be the effect of the phase noise related to the other parts in the circuit?

I have a SI5351 so I will try it on higher frequencies, it is all about the experiment :-)
Maybe I will share the results later.

Thanks for sharing your knowledge,
Chris PA3CRX

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